A zoetrope is a motion picture device providing a mechanical means to display animated imagery by successively revealing and obscuring individual images in a moving series of images. As is well known, a zoetrope comprises a vertically positioned cylindrical wall. The wall is perforated by a series of vertical viewing slits, regularly spaced around its circumference. The interior of the wall provides a surface to support a series of individual images, each comprising an incremental position in the path of movement of a depicted object. When the zoetrope is rotated around the axis passing through its geometric center and running parallel to the viewing slits, the interior surface of the wall may be alternately viewed through the slits and then obscured by the area of wall between the slits. Viewed through the moving series of slits, each successive image of the moving series supported on the interior surface of the wall is revealed as it reaches the same location where the image preceding it had been revealed.
If the zoetrope is rotated at sufficient speed, individual images are revealed for a brief enough period of time that the real motion of the series is imperceptible, and then obscured for a brief enough period of time so that each image persists in the vision of the viewer until replaced by the image following it in the series. Thus, the zoetrope utilizes stroboscopic and thaumatropic effects to make possible the experience of illusory motion.
The first U.S. patent for a zoetrope was issued to William Lincoln, assignor to Milton Bradley & Co. in 1867, (U.S. Pat. No. 64,117). The zoetrope was the most sophisticated and popular motion picture apparatus for several decades, surpassed at the close of the century by Edison's hand-cranked arcade Kinetoscope, and shortly thereafter by theatrically projected movies. The zoetrope remained popular however, and a variety of inexpensive versions of this amusement device have been developed and successfully marketed.
In 1910, 1917, and again in 1933, U.S. patents were issued for zoetropes that could be marketed and distributed as flat kits to be assembled for viewing by consumers. The first U.S. patent for such a zoetrope kit, U.S. Pat. No. 972,344, describes a zoetrope formed from a single rectangular sheet of material that can be cylindrically bent and attached at opposing short ends. Since the cylindrical structure of this zoetrope is maintained only by the elasticity of the sheet material, the wall cannot be folded for packaging and its erect diameter is limited to a dimension equalling less than 1/3.14 the length of the kit. This severely limits the size of a zoetrope that can be enclosed in an ordinary mailable envelope. Further, the means of erecting this zoetrope necessarily requires overlapping part of the wall, and since no secondary structure reinforces the cylindrical configuration of the erect zoetrope, it will tend not to assume a truly radially symmetrical shape, thus compromising its performance.
The other two patents (U.S. Pat. No. 1,214,636, issued 1910; and U.S. Pat. No. 1,925,136, issued 1933) describe improved kits, both comprising a zoetrope requiring the assembly of two separate pieces of pre-cut sheet material. In both descriptions, one of the pieces is a generally rectangular wall piece that, not unlike the wall piece described in the 1910 patent, must be connected by the consumer at opposing short ends. The other piece is a generally circular base which the consumer can attach to the cylindrical wall through a process of engaging various tabs and slots, thus providing structural stability for the erect drum. The base of the 1993 patent includes a fold line, an improvement which allows for a larger collapsible zoetrope to be enclosed in an ordinary mailable envelope.
Zoetrope kits similar to the ones described in the two later patents are still being marketed today, most commonly as novelty items in museum shops or as devices in science kits used to demonstrate certain principles of optics and sight. The process of assembling both these zoetropes requires a series of coordinated operations, some time and patience, and some glue or other external fastening means.
It would be desirable to have an inexpensive collapsible zoetrope that consumers may easily erect from a flattened form to an operational state in a few seconds without requiring gluing or any other external fastening means. Further, it would be desirable to have a collapsible zoetrope that when erected to operational form has substantially true radial symmetry; one that may be easily and repeatedly collapsed and erected with no substantial loss of operability; and one that may be made of satisfying size when erect and be enclosed in an ordinary envelope when collapsed. Such a zoetrope might alternately be made as small as a Christmas tree ornament or as large as a refrigerator box. Such a zoetrope might be easily stored and distributed, sent through the mail as a greeting card, enclosed in a book or magazine, given away as promotional material, used as a party favor or holiday decoration, incorporated into a kiosk display, or used to display an individual work of animated art. Preferably, the zoetrope should be packaged and sold in a collapsed state while being easily erected to its operating form.